This application claims the priority of German Patent Application 100 49 458.7, filed Oct. 6, 2000, the disclosures of which is expressly incorporated by reference herein.
The invention relates to a cushion for a motor vehicle seat comprising a ventilation layer, through which air can flow; ventilation channels, which pass through the cushion from a cushion bottom side up to an upper side of the ventilation layer, facing away from the cushion bottom side; sleeves, which are inserted into respective ones of the ventilation channels, each with a protruding collar on its closed upper end which rests on the surface of the ventilation layer; each sleeve including a sleeve jacket segment which passes through the ventilation layer to air passage openings; and miniature fans which are received in respective ones of the sleeves.
In a prior art cushion as disclosed in German Patent Document No. DE 197 45 521 A1 and corresponding U.S. patent application Ser. No. 6,206,465 B1, the ventilation layer, through which air can flow, is made of a space fabric. Each miniature fan is installed in a cylindrical sleeve, whose front end, facing the ventilation layer, is designed as a funnel. The funnel exhibits such a shape that a part of the air flow, guided to the ventilation layer, enters into the open cross section of the ventilate layer and the rest enters into this ventilation layer on the bottom side. Each sleeve is installed into a ventilation channel, which passes through a foam pad received by a cushion support, and empties, on the one hand, into the ventilation layer and, on the other hand, into the bottom side of the foam pad, facing away from the ventilation layer.
It has already been proposed for the class of cushion described above in German Patent Document No. DE 199 41 716.4 that the characteristics of the sleeves, receiving the miniature fans can be optimized with a thick ventilation layer made of rubberized hair filaments, alone or in combination with a warp-knitted fabric such that the sleeves are flexible in the axial and radial direction, e.g. by making the sleeves of rubber and by integrating spring bellows into the central sleeve section. In this manner, the miniature fans are held in the cushion without any force by means of the sleeves. Thus, in the occupied state of the cushion, the sleeves can slide in it without any shear forces acting on the sleeve and the fan housing. In the case of a seat load, the cushion and sleeve can be moved in relation to each other so that stress on the seat does not result in rattling noises. Due to the elasticity of the sleeve in the longitudinal and cross direction, the sleeves are flexible both with an axial load and with a cross load on the cushion.
A problem addressed by the invention is to realize, for a cushion with active ventilation of the aforementioned type, an integration of the miniature fans that guarantees the mostly noiseless operation of the miniature fans in the cushion even with the use of a thin ventilation layer made of a cushion material that is harder than rubberized hair filaments.
The invention solves this problem by providing a cushion for a motor vehicle seat comprising a ventilation layer, through which air can flow; ventilation channels, which pass through the cushion from a cushion bottom side up to an upper side of the ventilation layer, facing away from the cushion bottom side; sleeves, which are inserted into respective ones of the ventilation channels, each with a protruding collar on its closed upper end which rests on the surface of the ventilation layer; each sleeve including a sleeve jacket segment which passes through the ventilation layer to air passage openings; and miniature fans which are received in respective ones of the sleeves; wherein the ventilation layer is formed exclusively by a layer of fabric, the sleeves are designed rigidly in axial and radial directions, and the air passage openings in the sleeve jackets are formed by oblong holes which extend in the circumferential direction of the sleeve and have a hole width measured in an axial direction of the sleeve equal to or smaller than the thickness of the layer of fabric.
The cushion, according to the invention, has an advantage that in the case of a thin layer of warp-knitted fabric, used for reasons relating to space and cost, an optimal supply of air to the layer of fabric is guaranteed by means of the stiff sleeves which are installed into the layer of fabric. Another advantage of the cushion according to the invention is that shear forces, which are generated in the relatively stiff layer of fabric due to a load on the cushion, cannot effect a deformation of the sleeves, thereby relieving the miniature fans of any mechanical load. Hence, no rattling noises are produced, and the ventilation does not fail due to the fan wheels of the miniature fans jamming.
The preferred sleeves, which are made of plastic, exhibit only very little wall thickness despite their rigidity. They can be integrated into the layer of fabric so as to be compact, inconspicuous, and not very thick. The oblong holes in the sleeve jacket segment in the layer of fabric are designed in such a manner that, on the one hand, they enable adequate ventilation of the layer of fabric and, on the other hand, guarantee adequate rigidity of the sleeve.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.